The broad goal of TRD 4, Diffuse Optics Technologies (DOT), Is to design, fabricate and deploy camera- and fiber-based technologies that employ modulation of the spatial, spectral, and temporal frequency properties of light These technologies are complimentary to or can be integrated with, devices currently used In medicine and pre-clinical molecular imaging. These technologies enable detailed study of in-vivo metabolic activity across spatial scales in thick tissues by quantifying biochemical composition (e.g. oxy- and deoxy- hemoglobin, water and lipid content), molecular fluorescence and blood flow. By coupling spatial, spectral, and temporal frequency modulation techniques with advanced computational models, DOT provides access to absolute quantitation of absorption, scattering, fluorescence and speckle contrast (Figure 1). Our team has developed two primary technological approaches that interrogate in-vivo tissue over different spectral regions, depths and fields of view. The first of these is camera/non contact-based quantitative imaging known as Wide-field Functional Imaging (WiFI) that fuses Spatial Frequency Domain Imaging (SFDI) with Laser Speckle Imaging (LSI) and enables characterization of superficial (<5mm) tissue depths over wide (up to 100x100mm2) fields of view (1). The second is quantitative, fiber/contact-based broadband spectroscopy and imaging, known as Diffuse Optical Spectroscopy and Imaging (DOSI), which is applied to thick tissues over depths of several centimeters but with sparser spatial sampling (2, 3). Both approaches are noninvasive and enable absolute quantitation of tissue biochemical composition by using spatial and/or temporal modulation of light to characterize tissue absorption and scattering properties. Over the current five-year LAMMP funding period, we deployed purpose-driven DOT devices to scientific and clinical collaborators at several performance sites, including UC-lrvine, UC-lrvine Medical Center, Long Beach VA Hospital, Children's Hospital Orange County, UC-San Francisco, Dartmouth, University of Pennsylvania, and Harvard. New technologies, components, algorithms and translational clinical observations that were not available in the current LAMMP cycle, now enable us to advance and expand our DOT instruments. The proposed research will develop and deploy several new instruments that integrate these developments to provide unprecedented access to functional contrast mechanisms, localize the origins of biological signals and drive clinical/pre-clinical translation. The instruments are expected to yield new Insight into disease progression and therapeutic response in areas such as neuroscience, cancer, vascular disease, and metabolic syndrome; and provide feedback and guidance during surgical procedures.